To remove a team member's certification, click on Certifications in the left navigation menu. On the Certifications page, locate the certification you wish to remove from a team member and click on the name of the certification.
By default, the Team Members tab is selected. Locate the team member for whom you wish to remove the certification. Click the orange wrench icon in the Edit column. (Be careful to click on the orange wrench icon associated with the team member's certification and not the same icon for the certification itself.) Next, click on the red wastebasket icon.
There will be no confirmation to delete the certification but you will have a moment to undo the deletion.
Note: A certification for a team member can also be removed on the Certifications tab on the profile page for the team member.